Lantern



Feb. 15 1927.-

C. O. HARRINGTON LANTERN 7 Filed Nov. 21, 1921 2 sheets-sheet 1 Feb. 15,19.27. 1,617,595 v C. O. HARRINGTON LANTERN Filed Nov. 21 2,Sheets-Sheet 2 Patented Feb. 15, 1927.

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CLINTON O. HARRINGTON, CHICAGO, ILLINOIS, ASSIGNOB 'I'O ALDOBILT'COTiIiPANY,

OLE CHICAGO, ILLINOIS, A COBTEOBATION OF I LLTNOES. 1

; LANTERN.

Application filed November 21, 1921. Serial No. 516,837.

ployed, the axis of the light projection is usually directed toward someintermediate point on the curve so that the engineer may have the effectof the signal throughout as much lateral range as the spread of lightfrom the source permits. Such lanterns do not, however, provide amaterially great.

spread except where special projecting lenses are employed; or where anunusually large source of light is used. In such special cases theobjection exists of the increased costof the special construction, theincreased cost of maintenance, or both. Furthermore, such practicebringsinto the system special constructions at only special places, resultingin much unnecessary inconveniences. Among such special constructions arefrosted lamps and frosted lenses for spreading the light and also aprojecting lens provided on its outer surface with a plurality ofparallel ribs. i

The principal object of the present inven tion is to provide simple,easily operated and highly efficient means associated with a source oflight and its projecting lens for providing a spread of light which isrelatively great, and thus improve the efficiency of the signal. A morespecific object is to provide such advantageous means in a form whichmay be applied to lanterns now 1n use, with the said desired results.Another specific object is to provide such meansin a form which may bereadily removable and replaced from time to time as desired, and

by removal of the light-spreading means provide for the efiective andconvenient focusing of the lamp with respect to the lens and of thelantern as a whole with-respect to the area desired to be illuminated.Another specific object is to provide a form of light=spreading devicein which interchangeability may be had to effect a greater or lessspread accc -J ing to the particular situation. ,itsiioth r to provide alight sprsad 'ing device which may be positioned for operative usewithout any focusing operation and without a modification of theadjustments of I the lantern parts previously made. It is also an objectto provide a device which is of low cost and which may be cheaply andeasily installed. Other objectsfand advantages will appear hereinafterIn the accompanying drawings, which form a part of this specification,Figure l is a vertical sectional View, as on theline 11 of Fig. 2, of arailway signal'lantern of conventional form having a screen deviceconstituting .a specific embodiment of a pare ticular feature of noveltyas an element or as a device in its operative position; Fig. 2 is avhorizontal sectional view of the same device, as on the line 22 of Fig.1; Fig. 3 is a sectional view .as'on the line 3-3 of Fig. 1; Fig. 4k isan enlarged fragmentary view illustrating the effect of the screendevice.andlens in refracting the rays .of "light; .5'is a fragmentary view of.a part 'of Fig. 4 on .an enlarged scale; Fig. 6 is an enlargedfragmentary sectional view showing a.

modified form of screen; Fig. 7 is a fragmentary enlarged face view ofanother modi fied form of screen; and Fig. 8 is afra mentary section onthe line 8 8 of Fig.

The lantern body 10., the projecting: lens 11 and. the. source of light12 mounted on a base 13 are to be understood as being of the usual or ofany preferred construction. The source of light 12 is to be understoodasbeing at or substantially at the focus of the lens 11. Ordinarily thelamp .is mounted for adjustment in several directions so that thefilament at 12 may be conveniently brought to the focal point.

The specific feature of improvement is the provision of a screen as 14between the source .ofylight and the projecting lens.., It is not new toprovide some form of screen between the lens and the lamp, and I amaware that colored screens and screens adapted to dim the light havebeen so positioned. The present screen device as 14 is of a differentconstruction, however, and accomplishes adifferent result. V

The specific screen 14 sa transparent ele-' ment and may be considered asmall rectangular plate of'glass having a'pl irality of vertical ribs(Figs'l and 5) thereon.

. 4. is readily removablyheld in j 17, a pair of lateral cleats 18 and atop cleat 19, each cleat'being formed to overlie the glass and holdit'upon the frame 16. Should Vit'b e desired to remove the plate as 14;the

top cleat 19 is'removed, as by removing the small screw 20 holding it inplace, whereupon the plate may be lifted out of the guideways "formed bythe bottom and lateral cleats, and thereupon the lantern may be used.without the screen 1n such positions as do not particularly call for it,and, lmporcated as point. lh'e parallel ribs 15 will ordinarily beVertical as shown in, Figs. 2 and 3 since 1n railway signal work atleast it will ordinarily be desired to spread the .rays in the 'sidewiseor lateral directions. When it is desired to spread the light in up anddown directions the screen or plate 14 may be turned so that the ribs 15will extend 'in the horizontal directions, the plate 14 being square andfitting the carrying p frame in either position.

' drical lens. flVhile the number of these.

i lenses may vary to a considerable extent it is'preferabIe to providearelatively large Eachof the ribs'15 is a very small cylinnumber of themside by side in order to obtain the, desired uniform diffusion of light.

The. effect. of these small lenses is to bend the rays coming from thesource 12 so that as the lantern is viewed from in ,front the V lightappears to emanate from'a plurality -40 of sources as 12, 12 and 12 in aline, there oing; a large number of such apparent sources oflight fromonesideof the field to the other. 7

Without the screen in position the rays from the true source 12 divergein straight lines tothe lens 11. With the screen as 14 in place some ofthe rays diverge from the source to the lens in substantially thenormal'way while for the most part they are bent "from the true normalline of divergence, the result being that from each of the projections15 there is a multitude of diverging rays striking thelens, and these,

rays depart from the lensin a multitude of diverging directions. .Sofar; as the divergence of the. rays is concerned the effect is that ofmany independent sources of light.

Turning to Fig- 6 the plate 23 has a plurality of parallel rib-likeprojections 24 also constituting lenses. These ribs are shown ashaving aconcave surface'thereby bending the raysdivergingly. The ribs 24 may beinclined'in one direction only, as illustrated, instead of beingsymmetrical with respect to the optical axisof the lens, in which'casethe light will be diflused chiefly one side have their direction changedin a greateror less degree. depending upon the angle between the tace ofthe rib and the back of the plate. lVith such a construction the opticalaxis of the lantern may be directed at a distant po nt on a railwaycurve, and with lateral diffusion taking place pr1nc1- pally on one sideof the axis the light from the lens will be diverted so as to cover theportions of. the curve nearer' to the lantern as desired. V I i If itshould be. desired to spread the rays in all directions instead ofmerely horiZontallyor vertically a lens screendevice such as shown, forexample, in Figs. 7 and 8 may be employed, in which case the plate 26 isprovided on one surface with a plurality of' small spherical lenses 27,the efl'ect of which screen to the lens as though there were anindividual source of li ht at a multitude of points as viewed from infront of the lens, with a consequent wide spreading of the rays in alldirections.

illustrated are highly efficient for the purposes indicated, theinvention is-not l1m1ted to the specific characters of the particularscreen elements illustrated herein, and refincrease of spread in givendirections.

2. In a signallantcrn, the combination of a projecting lens, a source oflight for roj ecting rays therethrough, and ght-refracting means betweenthe lens and the source of light comprising a substantially transparentplate on one. surface ot'which are a plurality of relativelysmalllight-dispersing elements for givingthe rays emanating from the lens amaterially greater increase of; spread in given directions. a r

3. In asigna-l lantern, the combination of a projecting lens, a sourceof light for projecting light therethrough, and'light-refracting meansbetween the lens and the source of light comprising a' substantiallytransparentplate on one surface of which are a pluralit v of relativelylong and narrow light-dispers While the forms of lens screensspecifically 90 is to cause the rays to emanate from the ing projectionsfor giving the rays emanating from the lens a materially greaterincrease of spread in given directions than in other directions.

4. In a signal lantern, the combination of a projecting lens adaptedtoproject rays of light from an associated source in a substantiallycircular path in cross View, a source of light for projecting lightthrough the lens, and light-retracting means between the lens and thesource of light comprising a substantially transparent plate on onesurface of which are a plurality of relatively long and narrowsubstantially straight and parallel light-dispersing projections adaptedto increase the spread of light in given directions whereby thelightrays from the source define a path of lightwhich is'elongated incross View.

5. In a railway signal lantern of the character described, thecombination of a projecting lens, a concentrated source of lightsubstantially at the focus of the lens, and light-retracting meansbetween the source of light and the lens, and materially spaced fromeach thereof, for giving the rays emanating from the lens a materiallygreater increase of spread in given directions.

6. The combination of claim 5 hereof in which said light-refractingmeansare in the form of a substantially transparent plate havinglight-dispersing elements thereon.

CLINTON O HARRINGTON.

